reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git remote add efi https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git
        git fetch efi next
        git checkout efi/next
        b4 shazam https://lore.kernel.org/r/20241011224812.25763-3-jonathan@marek.ca
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/firmware/efi/libstub/